Difference between revisions of "Compiling a kernel"
From Linuxintro
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= Check prerequesites = | = Check prerequesites = | ||
* Make sure you have a compiler installed - [[open a console]] and issue | * Make sure you have a compiler installed - [[open a console]] and issue | ||
| − | yast -i gcc | + | [[yast]] -i gcc |
= Get the code = | = Get the code = | ||
* Download the kernel from ftp.kernel.org | * Download the kernel from ftp.kernel.org | ||
| − | wget ftp://ftp.kernel.org/pub/linux/kernel/v2.6/linux-2.6.27.tar.bz2 | + | [[wget]] ftp://ftp.kernel.org/pub/linux/kernel/v2.6/linux-2.6.27.tar.bz2 |
* unpack the kernel | * unpack the kernel | ||
bunzip2 linux-2.6.27.tar.bz2 | bunzip2 linux-2.6.27.tar.bz2 | ||
* unpack the kernel for the second time | * unpack the kernel for the second time | ||
| − | tar xvf linux-2.6.27.tar | + | [[tar]] xvf linux-2.6.27.tar |
= Build it = | = Build it = | ||
* configure the kernel | * configure the kernel | ||
| − | cd linux-2.6.27 | + | [[cd]] linux-2.6.27 |
| − | make oldconfig | + | [[make]] oldconfig |
* answer some un-understandable questions | * answer some un-understandable questions | ||
The sense of the step ''make oldconfig'' is to tell the kernel its configuration, e.g. which parts should be built as a module, which parts should not be built at all and the name of your special build. oldconfig takes over the settings from the running kernel that you can check with <tt>zcat /proc/config.gz</tt> if the switch EXTRACT-IKCONFIG is on. The settings for the new kernel are stored in the file ''.config''. E.g. a line <tt>CONFIG_LOCALVERSION="-thorsten"</tt> in .config would tell kernel 2.6.27 to call himself 2.6.27-thorsten. | The sense of the step ''make oldconfig'' is to tell the kernel its configuration, e.g. which parts should be built as a module, which parts should not be built at all and the name of your special build. oldconfig takes over the settings from the running kernel that you can check with <tt>zcat /proc/config.gz</tt> if the switch EXTRACT-IKCONFIG is on. The settings for the new kernel are stored in the file ''.config''. E.g. a line <tt>CONFIG_LOCALVERSION="-thorsten"</tt> in .config would tell kernel 2.6.27 to call himself 2.6.27-thorsten. | ||
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This will install the kernel for the ''x86_64'' architecture. | This will install the kernel for the ''x86_64'' architecture. | ||
* prepare the initial ramdisk | * prepare the initial ramdisk | ||
| − | cp System.map /boot | + | [[cp]] System.map /boot |
mkinitrd | mkinitrd | ||
This will build an initial ramdisk for all kernels contained in /boot. | This will build an initial ramdisk for all kernels contained in /boot. | ||
Revision as of 22:14, 4 January 2012
This is an example how to compile a Linux kernel. It has been tested for SUSE Linux 11.1 and kernel 2.6.27, but should work same or similar for every combination.
Check prerequesites
- Make sure you have a compiler installed - open a console and issue
yast -i gcc
Get the code
- Download the kernel from ftp.kernel.org
wget ftp://ftp.kernel.org/pub/linux/kernel/v2.6/linux-2.6.27.tar.bz2
- unpack the kernel
bunzip2 linux-2.6.27.tar.bz2
- unpack the kernel for the second time
tar xvf linux-2.6.27.tar
Build it
- configure the kernel
cd linux-2.6.27 make oldconfig
- answer some un-understandable questions
The sense of the step make oldconfig is to tell the kernel its configuration, e.g. which parts should be built as a module, which parts should not be built at all and the name of your special build. oldconfig takes over the settings from the running kernel that you can check with zcat /proc/config.gz if the switch EXTRACT-IKCONFIG is on. The settings for the new kernel are stored in the file .config. E.g. a line CONFIG_LOCALVERSION="-thorsten" in .config would tell kernel 2.6.27 to call himself 2.6.27-thorsten.
- compile the kernel,
make -j4
- Note
- on a virtual machine with two virtual CPUs @ 2.4 GHz, this lasted 55 minutes.
- compile the drivers
make -j4 modules
Install it
- install the drivers
make modules_install
- install the kernel
cp arch/x86_64/boot/bzImage /boot/vmlinuz-2.6.27
This will install the kernel for the x86_64 architecture.
- prepare the initial ramdisk
cp System.map /boot mkinitrd
This will build an initial ramdisk for all kernels contained in /boot.
- add an entry to the bootloader. Let's take grub's /boot/grub/menu.lst:
title 2.6.27-selfcompiled root (hd0,0) kernel /boot/vmlinuz-2.6.27 root=/dev/sda1 initrd /boot/initrd-2.6.27
